Precision spiral steel staircase

ABSTRACT

A rigid, stackable spiral staircase unit comprised of a hollow center support column, a plurality of horizontal steps welded to the support column, a pair of balusters welded to each step and connecting the adjacent steps, and a handrail welded to the top portions of the balusters in the form of a spiral. The end of the support column is provided with a mounting pin for journaled engagement with the column of an adjacent staircase unit such that several units may be conveniently stacked or nested together at the point of installation to provide a staircase of desired height.

United States Patent [19] Schneider June 26, 1973 PRECISION SPIRAL STEEL STAIRCASE [76] Inventor: Otto Schneider, 9204 Hines Road,

Baltimore, Md. 21234 [22] Filed; Sept. 17, 1971 [21] Appl. No.: 181,534

Primary Examiner-John E. Murtagh AttorneyClarence A. O'Brien and Harvey B. Jacobson ABSTRACT A rigid, stackable spiral staircase unit comprised of a hollow center support column, a plurality of horizontal steps welded to the support column, a pair of balusters welded to each step and connecting the adjacent steps, and a handrail welded to the top portions of the balusters in the form of a spiral. The end of the support column is provided with a mounting pin for journaled engagement with the column of an adjacent staircase unit such that several units may be conveniently stacked or nested together at the point of installation to provide a staircase of desired height.

8 Claims, 3 Drawing Figures PAIENTEUJuu26 ma 3.740.906

\M Fig] Of/o Schneider ma Wave; 19m

1 PRECISION SPIRAL STEEL STAIRCASE The present invention is generally related to staircase constructions and, more particularly, to steel fabricated spiral staircases.

In the past, a variety of staircase constructions have been provided, many of which were of bolted or riveted design for assembly at the point of installation. With substantial increases in labor costs, such staircases have become extremely expensive to assemble and install. Furthermore, these constructions were often weak and flimsy and tended to loosen with time, requiring periodic maintanence. While welded staircase constructions have been found to be more desirable from the standpoints of cost and durability, such constructions, in many cases, have been cumbersome to ship and difficult or impossible to install due to access problems encountered in partially or fully completed buildings.

It is object of the present invention to provide a novel spiral staircase construction comprised of rigid welded units which may be easily handled and which are adapted to be conveniently stacked or nested together at the point of installation.

Another object of the present invention is to provide a versatile spiral staircase unit which may be mass produced in convenient sizes and at a relatively low cost, and which may be easily shipped to a job site for installation with a minimum amount of effort and expense.

It is a further object of the present invention to provide a unique spiral staircase unit of heavy duty steel welded construction which is durable, long lasting, and easy to install, yet, relatively inexpensive to manufacture.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is an elevational view of the spiral staircase construction of the present invention.

FIG. 2 is a plan view of the spiral staircase as shown in FIG. 1.

FIG. 3 is a partial exploded perspective view illustrating the connection between a pair of spiral staircase units associated with the present invention.

Referring now, more particularly, to FIGS. 1 and 2, the spiral staircase construction of the present invention is generally indicated by the numeral and includes a pair of central vertical support columns 12 and 14 which are connected together by way of a joint indicated by the numeral 16. Preferably, each support column is comprised of a hollow cylindrical rigid steel member of a type and quality most ideal for welded construction. A plurality of arcuately-shaped horizontal steps 18 are welded to the support columns at their innermost arcuate edge portions indicated by the numeral 20. The outer edge portion of each step 18 is, preferably, arcuate in shape, and each step is provided with a pair of mounting holes 22 adapted to receive a vertically extending baluster 24, each baluster being welded to the step at an area 26 immediately surrounding the mounting hole 22.

Each baluster 24 is of predetermined length such that their top ends align in the form of a spiral. A spiral handrail 28 is welded to the top ends of balusters 24 to form a rigid spiral staircase construction. Of course, when the spiral staircase construction is comprised of two or more staircase units, handrail 27 may be split such as to permit easy assembly on the job site, as hereinafter explained. Such a split or joint in the handrail is indicated by the numeral 30.

Referring now to FIG. 3, the connection between individual staircase units can be seen in more detail. Each support column 12 or 14 is, preferably, hollow in construction and is provided with a mounting pin 32 rigidly affixed by welding or force-fit at one end thereof. After the initial spiral staircase unit has been installed on the job site, additional height may be added to the staircase by way of a second spiral staircaseunit, such as that including support column 12. The opening 34 at the bottom of support column 12 is adapted to snugly receive mounting pin 32 during installation on the job site. Also, the bottom end 36 of the lowermost baluster member of the upper staircase unit is adapted to align with mounting hole 22 provided in the top step of the lower staircase unit. As such, it will be appreciated that assembly of the staircase units on the job site is extremely simple to perform, requires a minimum amount of effort, and, thus, greatly reduces the installation costs. After the units have been properly fitted together they may be permanently welded into position, thus, tieing the two staircase units together as one rigid construction.

It will be appreciated, that the geometric arrangement of the staircase steps and baluster members provides additional rigidity to the overall construction. The steps are welded to their vertical support columns at points along a spiral path on the surface of the support column. Also, the steps are positioned such that they partially overlap each other longitudinally. This arrangement permits each baluster to be connected to a pair of adjacent steps, each baluster being welded to the step at the respective connection points. This greatly increases the overall rigidity of the structure since each step is rigidly connected to the adjacent steps immediately above and below.

From the foregoing, it will be appreciated that the spiral staircase construction of the present invention may be easily and inexpensively mass produced, thus, eliminating the tedious and expensive job of more sophisticated assembly at the point of installation. The spiral staircase units may be manufactured in a variety of standard sizes to accommodate a variety of overall spiral staircase height requirements. Furthermore, by providing standard staircase units which are not unusually large and which are not cumbersome to handle the problem of access into partially or fully completed buildings is eliminated. While the spiral staircase construction of the present invention eliminates the problem of sophisticated assembly on the job site, it also provides an extremely rigid, durable, and long lasting structure, not provided by conventional spiral staircase constructions of comparable cost.

The construction of the spiral staircase units is relatively simple and consists of horizontally positioning a support column on a support jig adapted for such purpose. The steps and balusters are placed into position and held in place by a fixture such that the steps are held perpendicular to the support column and the balusters parallel to the support column. The steps and balusters are then welded in place, after which the handrail is positioned and welded to the top ends of the balusters. The entire spiral staircase unit is then painted and readied for installation.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. A rigid spiral staircase construction comprised of a plurality of welded spiral staircase units, each spiral staircase unit including a vertical support column, a plurality of vertically spaced horizontal steps welded to said support column, a plurality of vertical balusters welded to said steps near the lower end portion of each baluster, and a mounting pin affixed to one end of the support column associated with each staircase unit, said pin extending into a mounting hole in the abutting support column to rigidly connect the staircase units together.

2. The structure set forth in claim 1 wherein the lowermost baluster of one staircase unit has a lower end which engages an opening in the top step of the underlying staircase unit immediately below, said lower end being welded in position in said opening after assembly of the staircase units.

3. The structure set forth in claim 6 wherein a pair of balusters are welded to each of said steps at a position adjacent to the outer edge portions of each step.

4. The structure set forth in claim 3 wherein one of each pair of said balusters is welded to one step at its lower end and extends through a second step immediately above, the other of the pair of balusters extending through said one step and being welded to a third step immediately below said one step to provide a rigid staircase construction.

5. The structure set forth in claim 4 wherein said handrail is welded to the top end of each baluster in the form of a spiral extending around said support column.

6. A rigid spiral staircase construction comprised of a plurality of welded spiral staircase units, each spiral staircase unit including a vertical support column, a plurality of vertically spaced horizontal steps welded to said support column, a plurality of vertical balusters welded to said steps near the lower end portion of each baluster, and fastening means at one end of the support column associated with each staircase unit for connection to support column of the adjacent unit to rigidly connect the staircase units together.

7. The structure set forth in claim 6 wherein each of said support columns is of tubular construction with said fastening means positioned on the inside thereof.

8. The structure set forth in claim 6 wherein the lowermost baluster of one staircase unit has a lower end which engages an opening in the top step of the underlying staircase unit immediately below, said lower end being welded in position in said opening after assembly of the staircase units. 

1. A rigid spiral staircase construction comprised of a plurality of welded spiral staircase units, each spiral staircase unit including a vertical support column, a plurality of vertically spaced horizontal steps welded to said support column, a plurality of vertical balusters welded to said steps near the lower end portion of each baluster, and a mounting pin affixed to one end of the support column associated with each staircase unit, said pin extending into a mounting hole in the abutting support column to rigidly connect the staircase units together.
 2. The structure set forth in claim 1 wherein the lowermost baluster of one staircase unit has a lower end which engages an opening in the top step of the underlying staircase unit immediately below, said lower end being welded in position in said opening after assembly of the staircase units.
 3. The structure set forth in claim 6 wherein a pair of balusters are welded to each of said steps at a position adjacent to the outer edge portions of each step.
 4. The structure set forth in claim 3 wherein one of each pair of said balusters is welded to one step at its lower end and extends through a second step immediately above, the other of the pair of balusters extending through said one step and being welded to a third step immediately below said one step to provide a rigid staircase construction.
 5. The structure set forth in claim 4 wherein said handrail is welded to the top end of each baluster in the form of a spiral extending around said support column.
 6. A rigid spiral staircase construction comprised of a plurality of welded spiral staircase units, each spiral staircase unit including a vertical support column, a plurality of vertically spaced horizontal steps welded to said support column, a plurality of vertical balusters welded to said steps near the lower end portion of each baluster, and fastening means at one end of the support column associated with each staircase unit for connection to support column of the adjacent unit to rigidly connect the staircase units together.
 7. The structure set forth in claim 6 wherein each of said support columns is of tubular construction with said fastening means positioned on the inside thereof.
 8. The structure set forth in claim 6 wherein the lowermost baluster of one staircase unit has a lower end which engages an opening in the top step of the underlying staircase unit immediately below, said lower end being welded in position in said opening after assembly of the staircase units. 